The present invention relates to an improvement in a pressure plate adjusting device for grain whitening apparatus.
Generally, in whitening apparatus, the reduction in the number of revolutions of the whitening roller within the apparatus takes place with the progress of whitening action. In order to keep constant or stable the load of grains in the whitening chamber, it is necessary to complement the increase and decrease of the load in proportion to the reduction in the number of revolutions of the whitening roller, and also to complement the increase and decrease of the load caused by such factors as the variation in the grain flow. To achieve this, the most convenient way is to increase or decrease the pressure of the pressure plate against the rice outlet of the whitening chamber.
In the conventional whitening apparatus, the above adjustment of the pressure plate has been performed by manual methods, i.e. by adjusting the adjustor of an elastic spring connected to the pressure plate or moving the weight mounted on the pressure adjusting rod carrying the pressure plate at its one end. Such conventional whitening apparatus has a drawback since it is difficult to effect adjustment and it necessitates fine manual adjustment requiring an experienced person in order to obtain the desired degree of whitening of grains.